I figured this out!
I was very confused by this because I had finished the barista career and still couldn't "make a coffee" or a latte.
There are actually two positions at the coffee bar. The default position is behind the espresso machine on the left. To "make a coffee" or a latte, you have to move your sim to the coffee grinder, which is the tall/cylindrical objet between the espresso machine and the tall pastry display case.
Unfortunately, I haven't met the criteria yet to post a screenshot. But take a closer look.
